Elevator system



June 1,1, 1929.

D. L. LINDQUlsT ET A1. 1,717,046

ELEVATOR SYSTEM Filed May 13, 1925 8 Sheets-Sheet l 1 JMW- JOUUUUUUL JUMMDUL flvmmR 50/ Exc/TER DRn/ING `307 'Mame 500 AzmmdT/c Hoon 330 roP MACH/N: laf

MOTOR /7 Cmsecurl 544/ 348 409 5Zl 0 .imp

577 s Mfr/145% SAFETY plm .5w/rch' 333 LEVEL we CAMS `June 1l, 1929.

D. L. LINDQUIST ET AL.

ELEVATOR SYSTEM Filed May 13, 1925 8 Sheets-Sheet 2 um NN nvamtordf June 11 1929- D. L. LINDQUlsT ET Ax.' 1,717,046

ELEVATOR SYSTEM Filed May 15, 1925 BvSheets-Sheet 3 MM JAM/VL C` Lamm heir abme/1j FWIW/lili.

June 11, 1929.

ELEVATOR SYSTEM Filed May 13, 1925 8 Sheets-Sheet 4 D. 1 LlNDQUlsT Er AL 1,717,046 t June l1, 1929. D. L.. LINDQUxs-r- ET AL 1,717,046

ELEVATOR SYSTEM Filed May 15, 1925 s sheets-sheet 5 June 11, 1929.

D. L. LINDQUIST ET AL E LEVATOR SYSTEM Filed May 15, 1925 s sheets-sheet 6 ALI'. ses! AA/M Lfgmm C', LGAAM @$131 heir @ttm/mud, NIW' F/a/5 h June 11, 1929. D. L. LlNDQ-Uls-r ET Ax. f 1,717,046

ELEVATOR SYSTEM Filed May 13, 1925 8 Sheets-Sheet 8v taken in connection with the accompanying,

\ his time and thought to the handling of the i Patented June 11, 1929. y

UNITED STATES PATENT OFFICE. y

DAVID L. LINDQUIST, OF HARTSDALE, NEW YORK,

AND EDWARD L. DUNN. OF EAST ORANGE, NEW JERSEY, AN D DAVID C. LARSON, OE YONKERS, NEW YORK, AS- SIGNORS TQ OTIS ELEVATOR COMPANY, 0F J EBSEY CITY, NEW JERSEY, A CORPORA- TION 0F NEW JERSEY.

ELEVATOB. SYSTEM.

application mea my 13, 192'5. serial No. 29,999.

This invention relates to glevator systems. As the art of electric elevztor'systems has developed` there has been an increasing tendency to relieve the operator in the car of va rious control operations. In some of the earlier systems the startlng and Vstopping of the car, the direction of travel of the ear and the rate ot acceleration and retardation were all controlled by the operator. Later the sysy tarding means and leveling devices to bring the car to rest at the landing. These developments greatly increased the efficiency of operation of elevator systems over systems of the earliest types. y

It was with the view of further increasing etieiency of operation that the present invention was developed, the system herein dis closed being particularly suitable for eleval tor service such as required in department stores.

One feature of the invention is to have the direction of travel of the car determined'automatically thus leaving the operator only.

the control of the initiation lof the starting operation and the selection of the landing at which a stop is to. be made.

Another feature resides in causing the car to operate between selected landings' as tery minals.

Otherl features and advantages will become apparent from the following description,

drawings wherein one embodiment ofthe invention is illustrated. 0 r

In buildings where'the service is heavy, 1t

is important that the operator give much of passengers so that they A.et to their destination in the minimumo time and with the also with parts broken away;

made only at the landings. except in the ercnt of emergencies. In accordance with this inventlon, in starting the operator is required to exercise his judgment only as to the time whcn'the starting operation should be ini'- tiated, such initiation being accomplished byy the same slmple motion of'a hand o ierated switch regardless of the direction'ot travel of the car. The stopping operation is automatic, the operator having only to select the floorat which it is desired to stop the car, the selection being made by releasing the hand operated switch in a certain zone of considerable length. In department stores where it is frequently desirable to stop at every floor, the stopping operation may be initiated immediately upon starting without further act of the operator, thus causing the car to stop automatically at each successive floor. 4

In the drawings z-- Figure l is a simplified schematic representation of the elevator system; I

Figure 2 is a front elevation of the director switch, with the cover plate removed;

Figure 3 is a view, partly in elevation and partly in section, taken along line 3-3 of Figure 2;

Figure 4 is a view in horizontal section, with parts broken away, taken along the line 4-4 of Figure 2;

Figure 5 is a front elevation of the direc tor switch reversing mechanism;

i Figure 6 is a plan View of the same;

Figure 7 is a detaihpartlyiin section,o a cam operated switch;

vFigure 8 is a detail in section, taken along line 8 8 of Figure 5,-of a portion of the connecting rod of the director'switch reversing mechanism Figure 9 is a'front elevation, with parts broken away, of the automatic oor stop machine;

AFigure 10 isa sidcelevation of the same,

- Figure 11 is a plan view of with parts broken away;

Figure 12 is a detail in lan of a brush; Figure 13g is a section, with parts in elevation, taken along line 13-13 of Figure 12;

Figure 14 is a ffragmental view taken the same, also along line 14-14 of Figure 11, of a brush and contact in engagement;

Figure 15`is a fragmental view of the arrangement of the pawl magnet limit switches and operating cam; p

Figure 16 is a diagrammatic representation of thel control panel, showino' particularly the relation of the coils and contacts of the various switches; and

VFigure 17 is a simplified diagram of the control system.

For a general understanding of the invention, reference may be had to`Figure 1 wherein various parts of the system are indicated by legend. The car is driven by the elevator motor. This motor receives its power from the generator of a motor generator set. An exciter, for supplying cur- `.rent toO the generator and elevator motor fields and the control circuits, is driven by lthe motor of the motor generator set. The

' driving motor .is started by a start control switch arranged in the car.- The starting of the car is under the control of an operator in the car, a master control switch being provided for this purpose. The master control switch is not employed to determine the direction of travel ofthe car, a separate' switch, to be known as the director switch, being provided for thispurpose. The director switch is moved to neutral position at the terminal fioors by the director switch hatchway Canis. A director switch motor is provided. for moving the director switch into revegsed position,

The car is stopped by means of the automatic floor stop machine at the intermediate floors and the director switch at the terminal floors. A consecutive-stop switch is provided in the car for controlling the operation of the automatic floor stop machine. A .safety switch is provided in the car for stopping the car in the event of an emers gency. An emergency switch is provided in the car for operatin the car with the gate and doors open. A director switch motor switch also is providedin the car for re-A veil-ging the direction of travel of the car a w1 l A leveling switch and leveling cams may be provided for causing the car tobe brought to the landing in the vevent that an exact stop has not been made.l The master control switch also controls the gate operating motor to e'ect the opening and closing of the car gate and well doors.

The system will be described as applied to a ten ioor installation. It is to be underdesignated as a whole by numeral 20, is enclosed in a suitable casing 21 and casing cover plate 22. The casing is provided with brackets 23 and bosses 24 arranged forl mounting the switch on the elevator car frame 11,9, as illustrated in Figures 5 and 6.

Within the casing and secured, as by screws,

cuits for the actuating coils of the up and down direction switches, respectively, and

contacts 34, 35, 36 and 37 controlling the circuits for the actuating coils of the accelerating switches. Two feed contacts 38 and 40,

similar in construction to the control contacts, are mounted on a support 41 of insulating material. This support, along with an intervening insulating strip 42, is secured to an arcuate boss 43 formed on the Contact support 27.

Segment 44, for bridging the above mentioned contacts, comprises an arcuate channel member, formed of an outer flanged portion 45, inner flanged portion 46 and connecting web 47 and a supporting arm 48. The outer iiang'e 45 is arranged for bridging either set .of control contacts, 32, 34 and 35, or 33, 36 and 37, while the inner iiange 46 is arranged to engage either feed contact 38 or 40. It will be observed that a circuit may thus be completed from either feed contact to the corresponding set of control contacts. Oil wipersl 561 and 51 are mounted on insulating support 41 to engage the contact surfaces of flanges 45 and 46 respectively. The supporting arm 48 is mounted on shaft 52 between two insulating plates 53 and 54. A projection 55 onV plate 54 extends through an aperture 56 in supporting arm 48 into a recess formed in plate 53. Shaft 52- extends through an inner aperture 57 formed` in projection 55 and through plate 53. Two other' projections 58 are formed on plate 54 and are' disposed diametrically opposite the projection55. These latter projections are similarly arranged to extend through apertures in supporting arm 48 into recesses in plate 53. A sleeve 60, arranged on shaft 52,.is formed with a flange 6l adjacent to plate 53. Flange 61, plate 53 and projections 58 are apertured to receive studs 62. Nuts 63, on the threaded ends of these studs, clamp the supporting arm 48, plates 53 and 54 and a separating washer 64 against the flange 61. It will be observed that with thisarrangement the segment 44 is completely insulated from the flange 61 and shaft 52. A pinion 65 is arranged on shaft 52 in abutting relation with the end of sleeve v60. The pinion, sleeve and segment are held in assembled `relation against a shoulder 66, vformed on shaft 52,-by meansof a nut 67 and llO locking pin 68. A key 70, mounted in aikeyway in shaft 52, forms a. driving connection between pinion 65 and sleeve 60, while the flange 61 and studs 62 form an operating connection between sleeve andsegment 44.

Pinion 65 is driven by means of a segmental gear 71. This gear is mounted on the inner end of a driving shaft 7 2, being secured thereto as by means of a through bolt 73. Shaft 72 extends through its supporting bearing 74 to the outside of the casing. An operating arm 75 ismounted on the outer end of shaft 72, being vsimilarly secured thereto as by means of' another through bolt 73. A roller 76, for engaging the director switch` hatch-way cams 77 (see Figure 1), is mounted on the free end of operating arm 75, Another operating arm 78 and a cam supporting segment 80 are mounted on the shaft 72 between the operating arm 75 and the bearing 74. One end of a connecting rod 81 is pivotally secured, as by pin 82, to the free end of operating arm 78. The other end of connecting rod 81 is secured to the director switch reversing mechanism as will be described later. Shaft 52 also extends through its supporting bearing 83 to the outside of the casing, the other end of the shaft being formed with a positioning flange 84. l/Vithin the casing, two friction plates 85 and 86 are mounted on sleeve 60, the sleeve being square in cross section to form a driving connection. .These friction plates cooperate with a stationary anl nular disc 87 to maintain the director switch in the position into which it has been moved. rIhe annular disc 87 is provided with apertured lugs 88. Projections 90, extending from base 26lit into the apertures of the lugs- 88 to hold disc 87 against turning. Friction plate 85, arranged on one side of disc 87, abuts against pinion 65. Friction plate 86 is forced against the other side of the disc, and the disc against friction plate 85, by means of springs 91 mounted on the studs 62. These studs extend into apertures 92 formed in friction plates 86. c

Adjustable abutment screws 93, mounted in I the sides of the casing 21, determine the limits of movement of the segmental gear 71. These screws form stops to prevent the disengagement of the contacts and bridging segment 44 by extreme movement of the segmental gear in either direction. A suitable opening 94 is provided in the casing 21 for'the va-v rious conductors leading to and from the director switch contacts.

A pair of of switches 95 and 96, identical inconstruction, are secured to the outside of the casing base'26 as indicated most clearly in Figure 5. Each switch is provided with an operating roller 97 disposed in the path of movement of cams 98 mounted on segment 80. Each cam 98 is adjustably secured to the segment as by means of screws 99. The inner l 101 is mounted on a frame 102, of'insulating material. The frame 102, comprises two side members 103 (one of4 the sides ynot being shown in order that the switch may be more clearly illustrated) and a connecting web 104.

The stem 105 of the contact holder extendsv through the web .104, its extended end being provided with nuts 106 for securing the holder to the frame and for. securing the ter-- niinal clip of a conductor. The movable contact 107 for engaging the stationary contact is carried by an operating arm 108. The arm 108 is-pivotally mounted, as by a pin 110,-on a bracket 111. Bracket 111 is provided with a stud 112 which extends through the web 104 and which is provided with nuts 106 for securing the bracket to the frame 102 and for securing the terminal clip of a conductor. Beyond its pivot point the operating arm 108 is formed with two lugs 113 between which extends a pin 1'14 for pivotally supporting the roller 97. A spring 115, tending tobias the switch l to closed position, 4extends between spring seats, one seat being formedv on the extended portion of the operating arm 108 and one on the bracket 111. Apertures 116 are provided for receiving the mounting screws.

Thus upon a cam 98 moving under the roller 97, the operating arm 108 "is rocked counter- 'clockwise about its pivot causing the separation of the contacts 101 and 107 and the compression of spring 115. As the cam moves oil' the roller the spring 115 rocks the operating arm clockwise causing the reengagement of the contacts.

Referring to Figures 5 and 6, the preferred form of director switch reversing mechanism will be described. The director switch motor 117 is mounted on a support 118 se` Cured to the car frame 119. One end of the motor shaft has secured thereto a pinion 120. The motor operates a segmental gear 121 through pinion 120, the segmental gear being `pivotally supported by abracket 122 dependlng from support 118. The segmental gear 121 in turn operates the director switch.

through the connecting rod 81 and arm 78. The connecting rod 81 comprises an end piece 123, pivotally mounted on a pin 124 provided on the segmental gear 121, a rod 125', buil'er spring 126, and butler springyoke 127. As

ice

I to slide in the cylinder'132 formed in the yoke 127. The buffer spring 126 is disposed in an opening 133 provided in the yoke 127 and eX- tends `between washers abutting against the shoulder on rod 125 and the shoulder formed by thepiston 131. The purpose of this arrangement is to absorb any shocks caused by director switch roller 76 with the car quite a distance from the terminal landing, the distance depending upon lthe particular installation. During downward movement of the car, the initial engagement of the camand roller causes the director switch to be moved linto a position to cause a reduction in the speed ot the car. From this point of engage,I

nient, the cani 77 slopes gradually to the left down to the point where it moves the director switch to neutral position. From this latter point, the cam is vertical, the director switch being moved into reversed position by the director switch motor 117 'as will be described later. rltlic cam at the top ioor isA identical in construction but reversed so as to move the director switch from up position into neutral position.

1n operation, assume that the director switch is in down position, as indicated by roller 76 and operating rain 75 in broken lines, Figures 2 and 5, and in full lines in Figure 6, it being noted that thel rear view of the director switch is illustrated in Figure 5. In this position, flange 45 bridges control contacts 32, 34 and 35 and flange 46 engages feed contact 38. As the car approaches the bottom floor., roller 76, engaging cam 77, is carried gradually to the left. The initial movement of arm 78, due to the engageincnt of the cam and roller, causes the yoke 127 to slide to the left on the rod 125 and piston 131, the portion of the yoke forming the right end of opening 133 acting through the washer to compress thespring 126 against the shoulder formed on rod 125. By employing the initial force to compress the spring in this manner, the inertia of the parts of the reversing mechanism is gradually overcome and the movement of arm 78 is transmitted to the director switch motor through segmental gear 121 without strain. As a result of the initial movement of roller arm 75, the segmental gear 71 rotates segment 44 in a counter-clockwise direction. In this manner the circuits controlled by contacts 35, 34 and 32 are broken in the order of the -contacts named. As the roller arm is moved into neutral position fiange 46 moves off feed Contact 38.

Motor 117 is energized, in'a manner to be described later, to'inove the director switch from neutral'intoaip position. IThe initial movement of the segmental gear 121 caused by the rotation of motor 117 causes the rod position, similarly indicated by broken lines in Figures 2 and 5, segment 44 is caused to engage contacts 40, 33, 36' and 37, preparing the control circuits for up operation o the car. The Vfriction plates 85 and 86 and disc 87 permit the movement of the segment 44 but, after the reversing operation, hold it in reversed position. Under normal operation, therefore, the segment44 remains in up position until similarly but oppositely moved by the liatchway cam 77 and motor 117 at the top Hoor into down position. Again, the friction plates and disc maintain the switch in this last moved position. rElius the director switch is normally in one of its'on positions.

The director switch motor is deenergized,

upon the completion of each reversal or thel director-switch, by the opening of either lswitch 95 or switch 96, depending on the position into which the director switch is moved. As previously explained, switches are opened by the engagement of their operating rollers 97 and the cams 98. With the director switch in one of its reversed positions, the corresponding switch 95 or 96 is maintained open by vitscani 98, as illustrated for switch 95 in Figure 5. As will be these described in conjunction with the description ot operation of the system as a whole, means are provided for causing the motoi` 117 to reverse the director switch at any point at the will of the operator in the car. 1t is to be noted however that the director switch cannot be reversed into its former position at the terminal landings due to the fact that the vertically extending portions of the hatchway cams 77 act as sto s. stop machine may e arranged to cause the motor 117 to reverse the director switch at any oor as will be described later.

. Reference may now be had to Figures 9 and 11 inclusivewhichillustrate the various details of a vpreferred form of automatic Hoorstop machine. This machine, designated as a whole by the numeral 135, comprises a trame formed by a base member 136, four standards 137, 138, 140 and 141 andl a top member 142.` The standards are secured in sockets formed in bosses 143' on base member 136 and sockets z formed in bosses 14.4 'on top member 142.

Eight switches are provided on the machine,

The automatic :door

and the down automatic first slow-down switch 150, second slow-down switch 151, stop switch 152 and door sequence switch 153.

Referring particularly to Figure 9 the up automatic switches 145,146, 147 and 148 are mounted on a bracket 154 Secured `to top vn'ien'iber 142 as by bolts.' Each switch com'- prises a stationary contact 155 and a movable contact 156. These contacts may be of any well known construction. 'The stationary contacts are mounted on an'insulating Contact plate 157 supported by the bracket 154. Each stationary contact is providedwith nuts 158 for securing the contact to the Contact plate and For connecting the respective switch in the system. w Each movable contact is mou-nted in an arm 160 of acontact lever, lever 161 being tor the first slow-down switch, lever 162 being for the second slow-dowi.' switch, lever 163 being for the stop switch andlever 164 being for the door sequence switch."

lith the switches in closed positions, each movable contact is pressed into engagement with .its corresponding stationary contact by means of a spring 165. Each-movable contact is insulated from its contact lever' and'is connected, as by a flexible conductor 166, to a corresponding binding post 167 on contact plate 157. All the contact levers are pivotally mounted on a pin 168 supported by arms 170 depending from bracket 154. The other arm 171. of each lever is enlarged to form a weight. Each weight acts as a bias tending to move its respective switch to-closed position. Also pivotally mounted on pin 168. preferably between Contact levers 162 and .163, is a bell cra-nk lever 172. The vertical arm 173 of the bell crank lever is T shaped, the cross member 174 of the T being provided with lugs 179 which extend intoithe paths of the contact levers. Abutment screws 175, 17 6, 177 and 17 8, adjustably mounted in the arms 160 of contact levers 161. 162, 163 and 164 respectively, are arranged for engagement by the lugs 179 during the operation of the switches Theabutment screws are preferably adjusted so that rst screw 175, then screw 176 and then screws 177 and 178 are engaged bythe corresponding lugs 179 on the cross member 174 to cause the consecutive opening in the order named of the first slowdown switch 145, the second slow-down switch 146 and then simultaneously thestop switch 14.7 and door sequencel switch 148 respectively. It is to be understood that retin( '.nents of adjustments may be made to suit the operating conditions of the particular. installation. A socket 180 is pivotally mounted on the horizontal arm 181'of bell crank' lever`172. A vertical tube 182 is secured in socket 180,

as by means of a pin 183. This tube extendsA into and is similarly secured in another socket 184. The socket 184 is pvotallv mounted on the horizontal arm 185 of a-bell crank lever 186. Bell crank lever 186 is pivotal-1y mpunted' between supports 187 formed on base member 136. l

.The down automatic switches 150, 151, I

152 and-153 are identical in construction with the corresponding up automatic switches 145, 146, 147 and 148, above described, and are similarly mounted on bracket 188. The mechanical construction of the closing mechanism is similar. The horizontal arm 190 of the top bell crank lever 191 and the horizontal arm 192 of the bottom bell crank lever 193, however, extend to the left instead of to the right as do the corresponding arms of bell crank levers 172 and 186. Thus to open switches 145, 146, 147 and 148, tube l182 must move in the up direction as indicated, while to open switches 150, 151,- 152 and 153, tube 194,"extending between levers 191 and 193, must move in theV down direction. The depending arms 195 of the bottom bell crank levers 186 and 193 are joined by means of a cross rod 196. rWith the cross rod connection, tube 182 must be pulled in the up direction in order to efect the downward movement of tube 194 and, conversely, tube 194 must be pulled in the up direction in order to effect the downward movement of tube 182. Thus the weight of one tube is counterbalanced by the weight of the other. An adjustable screw stop 197 extends through a connecting web 198 for supports 187 into abutting relation with end piece 200 provided on cross rod 196. A Weight 201, provided in the nllower end of tube 182, serves to unbalance tubes 182 and 194 and acts as a bias tending to maintain the' switch opening mechanlsm 1n normal position, i. e., the position 1n which end piece 200 engages screw stop 1-97.- The screw 197 is so adjustedA that, with the switch opening mechanism in normal position, the automatic switches will be free to return to closed positions. A preferred form of mechanism for causing the operation of the switches will now be described.

Referring to Figure 1, the automatic floor stop machine is driven preferably by means of two steel tapes 202 and 203-attached to the car. Tape 202 extends from the'top of thel carto an overhead sheave 204 around which it is wound in a manner similar to the winding of a measuring tape. The other tape 203 extendsfrom the bottom of the car around a tension sheave 205 and then up to a secondoverhead sheave 206 upon which it is similarly but oppositely wound. These overhead sheaves are keyed to the operating shaft 207 of the automatic floor stop machine, one tape winding up as, the other unwinds in the driv-4 ing operation. This silent drive 1s as pos1- bearings 210 and 211 respectively fort-he shaft 207. The pedestal 208 is further arranged to receive a vei'tical bearing 212 and to support a ball thrust bearing 213 Vfor screw 214. IThis screw extends vertically into a bearing 215 formed in the top member 142. A beveled gear 216 is secured, as by pin 217, to the lower end of screw 214. Another beveled gear 218, engaging gear 216 in a driving relation, is secured, as by pin 220, to operating shaft 207. Operative engagement between the beveled gears is maintained by positioning collars 221 secured on shaft 207.

A crosshead, (see Figure 11), comprising a forked end 222, a nut 223 and frame 224 ext-ending therebetween, is arranged to be driven by screw 214; The forked end 222 engages a vertically extending bar 225 to form a guide for the crosshead. Bar 225 is Secured to lugs 226 and 227 formed on base member 136 and top member 142 respectively. A. pawl magnet frame 228 is carried by the crosshead nut 223, being secured thereto as by bolts. Frame'228 is arranged to receive the pawl magnet 230. The pawl magnet comprises a coil 231 and central core 232. Non-magnetic plates 233, positioned at each end of the pawl magnet, are secured to the frame 228 as by means of through bolts 234.

These plates form a mounting for the pawl magnet, being' provided with recesses 235 into which the core 232 extends. The pawl Y magnet armatures 236 and 237 are. pivotally mounted, as by means of pins 238, on arms 240 extending outwardly in opposite directions from the top and bottom of Yframe 228. The non-magnetic plates 233 further serve as spacing members to prevent armatures 236 and 237 from being held in by residual magnetism. Armature 236 extends inwardly from its pivot point to form an arm 241. The end of arm 241 is bifurcated to-slidably v engage a sleeve 242, the sleeve being mounted on a pin 243 secured in frame 228. lA. spring 244 is arranged on pin 243 above the sleeve in such manner as to be compressed by arm 241- when the armature is drawn in by pawl magnet 230, Between its end and pivot point, the arm is enlarged to form a Weight 245. Spring 244 and weight 245 act to move the armaturegi'nto unattracted position when the pawl magnet coil 231 is deenergized, the spring acting to give rapidinitial movement. An adjusting screw 246, provided in arm 241,

engages frame arm 240 to determine the amount of out-Ward movement ofthe arma- Ature. Armature 237 is similarly arranged with an arm, slot, pin, spring and adjusting screw but is reversed. Thus its weight 247, in order to function properly, extends outwardly from the pivot point. Pawls 248 and 250 vare secured, as by screws, to armatures l236 and'237 respectively, paWl 250 vbeing reversed to correspond with its armature. These pawls, with armatures 236 and with collars for the second to the tenth doors 7g inclusive for operative engagement by pawl 250,to stop in the up direction and tube 194 with collars for the ninth to the first floors inclusive for operative engagement by pawl 248to stop in the down direction. Each col- 7 lar 251 may be formed with a U bolt 2.52 and clainpingplate 253 so as to be readily adjustable.

The automatic first slow-down switches 145 and 150 are' arranged in the circuits for the actuating coils of second and third ac-v celerating switches. lrlhe automatic7 second slow-down switches 146 and 151 are arranged in the circuits for the actuating coil of the first accelerating switch. stop switches 147 and 152 are arranged inA vthe circuits for the actuating coils of the up and down direction switches respectively. rlhe automatic sequence switches 148 and The automatic S5 153 are' arranged in parallel relation in the 90 circuit for one of the coils of the door contact sequence relay. rl`hese circuits are clearly shown in the diagram'in Figure 17, reference to which will be had later. Y

ln operation, assuming that the car is rung5 ning in the up direction, the crosshead nut 223 is driven upWardly,-by-the steel tapes 202 and 203, shaft 207, beveled gears 218 and 216 and screw 214 in the manner previously indicated, in proportion to the movement of the elevator car. APawl magnet coil 231 being energized, the pawl vmagnet armatures 236 and 237 arelin their attracted positions and the pawls 248 and 250 do not engage the stopping collars. Assuming that it is desired to stop at the seventh floor, as the car approaches the seventh lioor stopping zone, the operator centers the car switch causing the deenergization of the pawl magnet coil.

rlhe operation ofettecting the energizationfno and deenergization of the pawl magnet will description of operation ofthe system as a whole. Pawls 248 and 250 are now forced out into their unattracted or stop positions by the armature weights and springs.; This n is the position illustrated in Figure 9. As v the crosshead is driven farther in the up direction', pawl 250 engages the seventh floor stopping collar 251 on tube 182. The tube 147 and door sequence switch 148 in the order 125 named. T he car, and therefore the crosshead, is then brought to a stop in a manner to be described later. It will be noted that the bell crank-levers 172 and 186 are moved counter-clockwise about their pivots, ,during Abe set forth in detail in connection with the is finally withdrawn from operative engagement with the pawl vby the movement of the levers. The back surface 254 of each-pawl is so inclined that, for example in the above operation, as the back surface of pawl 248 strikesa stopping collar, the pawl slides over `the collar without operative engagement.

Automatic switches 150, 151, 152 and 153 are opened, due to the connectionbetween tubes 182 and 194, at the same time that Y switches 145, 146, 147" and 148 are opened.

As the control circuits in which switches 150, 151, 152 and 153 are included are broken, due

, to the fact that the director switch is in up position, the opening of these switches is without effect at this time.

The automatic switches are heldin open position until the pawl magnet coil 231 is again energized. When this coil is energized pawl 250 is withdrawn from operative engagement with the seventhiloor stopping collar. `Weight 201 then acts to move tube 182 downwardly'and tube 194 upwardly until stopped by the engagement of screw stop 197 and cross rod end piece 200. Bell crankl levers 172 and 191 are thus moved out of operative engagement with the abutment screws, permittin the automatic switches to close. It is to Ibe noted that, due to abutment screws 177 and 178 having the same ad.

justmeut, the stop switches and door sequence switches close simultaneously.

Referring now more particularly to Figurcs 10l and 11, a plurality of bars 255 of insulating material are arranged between:

standards 140 and 141 to form mountings for the automatic fioor stop machine stationary contacts. Both of these standards are'provided with a plurality of adjustable collars 256, the corresponding collars on each standard being arranged in horizontal alignment to support the insulating bars 255. The stationary contacts are arranged. on the bar s 255 in two columns, those in column 257 being designatedreversing contacts and being arranged inthe control circuits for the clirector switch motor 117, and those in column 258 bein designated stop contacts and being .arrange in the control circuits for effecting the deenergization of the pawl magnet. The stationary vcontacts are secured to the insulator bars 255 as by bolts 260. These bolts also secure insulating plates 261 on top of the contacts in column 258. Thestationary contacts are engaged by traveling brushes to etectthe automatic stopping of the car and the reversal of its direction of travel. For

convenience of description stationary con-` tacts are illustrated for only the secondand ninth of the intermediate floors, i t being understood that the contacts for the intermediate floors are arranged to suit the require-V ments o'f the particular installation.

The traveling brushes for engaging the staltionary'contacts are mounted on a panel 265 is provided for engaging the reversing' contacts in column 257 while two brushes, up

stop brush 266 and down stop 267, are pro.- i

vided for engaging the stop contacts in column 258. The system is arranged so that,

of the stop brushes, only the up stop brush 266 is alivey during up motion of they carand only the down stop brush 267 is alive during down motion of the car. The brushes 265, 266and 267 are ident-ical in construction, the details of one of the brushes being illustrated in Figures '12 and 13.

Referring to Figures 12 and 13, the brush Contact pieces 268 are pivotally mounted in the brush frame 270, as'y by means of a pin 271 supported by the frame arms 272. The brush contact pieces are preferably provided with slots 27 3, through which the pivot pin 271 extends, so as to permit'their longitudinal as well as pivotal movement. Longitudinal recesses 274 are formed in the brush contact pieces to receivesprings 275. .These springs abut yieldingly against pivot pin 271, tending to maintain the contact pieces in their outer positio The frame arms 272 and washer 276 close slots 273 to maintain the springs 275 in position.

A centering blade 277 for the brushcontact pieces is loosely mounted on guide bushing 278. The bushing 278, along with a washer 280, is secured to the yoke 281 of the brush frame 270, as by means of a screw 282. A.

compression spring 283 is mounted on bushing 278 between centering blade 277 and washer 280. The outer end of the centering blade is bent in suoli manner as to form continuous engagement with the elongated surfaces yof the contact pieces. Thus, whenfurther to compress the spring 283 during this operation. Thus, as the brush leaves the stationary contact, the compression spring causes the centering blade to restore the contactk pieces to their central position. As the circuit completed by the brush and stationaxycontact is from the frame and centering `blade into the contact pieces, it will be seen that the circuit is not broken by rocking the contact pieces in either direction about their pivot pin. ln Figure 14, the up stop brush 266 is illustrated in rocked position in, engagement with one of the stationary stop contacts.

Referring to Figures 11 and 15, a pair of switches, 284' for the top ioor and 285 for the bottom floor, are mounted on standard 138, the switches being of the same construction as the switch illustrated in Figure 7. Each switch is mounted on a plate 286 by means of through bolts 287. Eachv plate is adjustably secured to the standard 138 by means 01"' a U bolt 288. A cam 290 for engaging the rollers 97 of the switches is secured, as by screws, to a prong 291 ot the forked end 222 of the ci'ossliead. The switches 284 and 285 serve as limit switches to insure the deenergization of th'e pawl' magnet upon the car reaching the terminal landings. As will be seen from later description, the engagement of a stop brush and stop contact at a terminal landing serves substantially the same purpose as the opening of the corresponding switch 284 or 285, so that the stop contacts at the terminal landings may be omitted if desired.

In operation,assumiiig that the car is moving in the up direction, the crosshead,

and therefore the cam 290, brushes 265, 266

' tering thecar-switcli.

and 267 and pawl magnet 230, is moved upwardly in proportion to the movement of the elevator car as has previously been explained. Stops at floors between the iirst and'tenth are then made by the operator cen- As the car approaches the tenth floor, the contact pieces' of the up stop brush 266 strike the insulating bar 255, rock and sweep across the tenth loor stop contact 294 and the cam 290, carried by the cros'shead, causes the opening of' switch 284. The engagement of the brush and contact and Vthe opening of switch 284 causes the circuit for the pawl magnet coil to bek broken so that deenergization of theV .pawlimagnet is assured regardless of the positionof thecar switch. The automatic switches therefore are opened in the manner previously described. Although the automatic Hoor stop `machine may act to stop the car at tlie terminal landings, it is preferred to employ the director switch for this purpose. The stop is insured, however, by the opening of the automatic switches. Before the car reaches the tenth floor landing, 'brush 265 engages the ltenth floor reversing contact 295, preparing `a circuit for tlie"direct or switch motor. This circuit is completed by one of the control switches during the stopping operation to move the director switch from neutral position, where it has been moved by the hatchway cam 77, into reversed position. A

avancee stop at the first `floor with the caimoving downwardly is made in a similar manner.

If it is desired to have the-car operate between the second and the ninth iioors, the stop and reversing contacts for the second andv the ninth vfloors are rendered alive in a manner to be described later. As the car approaches the ninth ioor, the contact pieces of the up brush 266 strike the insulating bai' 255, rock and sweep across the ninth floor-stop contact 292. The engagei'nent of the brush and Contact causes the circuit for the pawl magnet'coil to be broken so that deenergization of the pawl magnet is assured regardless 'of the position of the car switch. Since the stopping collars 251 for the floors are positioned so as to cause the opening of the first slow-down switch 145 or 150 with the car at a definite distance from the floor, the stop brushes and contacts are arranged to engage at such time as to insure the release of the pawls before the corresponding stopping collars are reached. As the car continues its movement, the automatic switches 145, A146, 147 and 148 are opened insequence, as previously described, causing the slow-down and lstop of the car. Before the car reaches the ninth floor landing, brush 265 engages the ninth floor reversing contact 293, preparing -minals Insuch an event, stop contacts and reversing contacts are provided on the automatic floor stop machine for each Hoor. Also means are provided for each oor for ren-V dering these contacts alive, as will be seei'i` from later description.

The reversing contacts are preferably made longer than the stop contacts to insure their engagement by brush 265 when'the control switches operate to complete the circuit for the director switch motor, these contacts and brush 265 being positioned so as to remain in engagement with the car at rest at the floor. The brushes are caused to rock and sweep across` their corresponding contacts in order to insure positive engagement.

When the car is stopped at a terminal landing, for example floor ten, the contact pieces of brush 265 are in engagement with contact '295 and are therefore in a rocked position.

n spondin floors, the insulating bars 255 being adjuste on standards 140 and 141, by means of the collars 256, to correspond. The leads (not shown) for the pawl magnet coil 231 are connected to certain of the binding posts on panel 262. The other binding posts are provided for the brushes mounted on the anel. Flexible conductors (not shown) extendp from these binding posts to similar binding posts (not shown) on panel 296. The flexible conductors are suspended in very much the same manner that flexible cables are suspended from an elevator car. Panel 296 is secured to standard 138 as'bymeans of a U clamp 297.

Reference may now be had to-Fi ure 17 which illustrates diagrammatically t e various control and ower circuits. No attempt is made in this gure to show thecoils and contacts of the electromagnetic switches in their associated positions, a straight diagram beingaemployed whereinlthe coils and contacts of the various switches are separated in such a manner as to render the circuits involved relatively simple. For a clearer understandin of the invention, the stationary contacts o the switches are illustrated in cross section. The relation of the coils and their contacts may-be seen upon reference to Figure 16, whichl illustrates the arrangement' of the switches on the -control panel. These electromagnetic switches have been designated as follows 'f A,-potentia1switch,v r l B- -up direction switch,

@down direction switch, D-first acceleratingswitch,`

4E--second accelerating switch, f F--third acceleratin switch, H-motor field switc A I-door contact sequence relay, J-minimum current field relay, K--driving motor starting switch, L-driving motor running switch, M-driving motor starting relay, N--protective relay, O-accelerating relay, P-up non-interference relay, Q-down non-interference relay, R--slow`down switch, S-load switch, T--leveling switch motor relay,

V-gate motor switch, W-maintaining relay, X-series field relay,y Y-series field switch, Z-Jspeed control switch, US-up stop switch, DS-down stop switch, LU-up slow speed leveling relay, LD-down slow speed leveling relay,

LF-fast speed leveling relay.

Throughout the 'description which follows,

pairs.

theseletters, in addition to the usual reference numerals, are a plied tothe parts of the above enumerate switches. For example, contacts B 438 are contacts on the up -The electromagnetic switches are all shown in their deenergized positions. Y

An alternating current driving motor 300 of the squirrel cage type and a variable voltage direct current generator 301 constitute a motor generator set, as illustrative of one form of power supplv suitable for the present system. 302, 30 and 304 are the alternating current mai.1 s, resistances 305 being arranged in the mains for the purpose of starting the driving motor. The elevator motor is desi nated y the numeral 306. An exciter 307, riven by the motor 300, is employed to supply current for the separately excited fields, 308 for the generator and 310 for the elevator motor, and for the control circuits. The armature of the exciter is designated b the numeral 309. The generav 326 and 327, is provided for controlling the, f.- v.

strength of the generator separatel excited field and therefore the voltage applied to the elevator motor armature. Resistances 328 and 329 are arranged in series with the ele, vator motor field. 330 is the release coil `for the elevator motor electromagnetic brake.

' Coil 330 is provided with discharge resist-I ances 331, 332 and333 for controllingthe apv plication of the brake under; different condi# tions of operation. Coil 330 is provided also with a cooling resistance 334.V 336 is the armature and 337 is the field of the motor 335 for moving-the rollers of the leveling switch so as to clear the leveling cams. The armature of the ate operating motor 338,is designated byV the numeral 340, thev field being designated 341. Various safety and emergency switches and door and gate contacts ma be employed, reference to which may be had7 in connection with the descriptionof the various circuits and of the operation of the system.

Referring briefly to Figurev 1, the master I control switch, designated as a whole by the numeral 342, comprises four airs of contacts 343, 344,345 and 346 an contact bars 347 and 348 for brid 'ng the contacts of the The contact ars are mounted on a pivoted segmental support 350, of insulating material, the supportbeing operated by means of the' control handle 352. It is preferred to provide centering springs (not shown) on the master control switch to cause c i tion Hl. v Upon counter-clockwisJe movement of the switch to position L the contact bar 348 bridges contact 345 to cause the loperation of the gate closing mechanism. Upon further counter-clockwise movement of the switch to position II, the contact bar 347 bridges contacts 344 and the contact bar 348 bridges contacts 346 to cause the starting of the car. It

is to be noted 'that the master control switch is always moved in the same direction, -i.- e., counter-clockwlse, to start the car. Upon reverse or clockwise movement of the switch l to position HLthe contact bar 347 bridges contacts 343 to cause the operation of the gate opening mechanism. The manner in which these operationsare eiected Will be described later.

Referring back to Figure 17, assuming that the control switches 353 and 354 are closed, in order to start the driving motor 300, the start control switch 355 in the car is closed.- A circuit is thus completed for the actuating coil M 356 of the driving motor starting relay and may be traced from alternating current main 303, by way of line 358 through switches 355 and 353, coil M 356 and contacts N 361, to .main 304;' The relay operates to cause the engagement of contacts M 362 completing the circuit for the actuating coil K' 363 of the driving motor starting switch, and the engagment of contacts M 364 preparing the circuit for the actuating coil L 365 of the drivin motor running switch. The circuit for Ycoil K 363 may be traced from alternating current main 303, line 358, by way of line 366 through contacts M 362, coil K 363 and contacts L 367, back to line 358, contacts N 361, to main 304. rlhe switch K operates immediately to cause the engagement of contacts K 368, K 370 and K 371 connecting the stator of the driving motorto the power mains through resistances 305 and completing the circuit for coil L 365. rlhe circuit :tor coil L 365 may now be traced from main 302, contacts K' 368,-one of the resistances305, by way of line 372 through coil L 365andcontacts M 364, another one of the starting reslstances 305, contacts K 370, to main'303.

does not operate im- ,inedlatel the voltage a plied to its'actuat- 111g coil eing of low va ue due to the high potentlal drop over resistances 305 during the startlng of themotor. As the driving motor approaches full speed, the current in the stator windings is reduced raising the voltage across co1l L 376 to 'by-pass resistances 305 and connect Y 365, causing the switch L to operate".

The .switch L upon operation, causes'v the engagement of power contacts L 374, L 375 and 35 f arranca Ythe driving motor directly vto the mains.

relay. The switch K drops out separating contacts K 368, K 370 and K 371 to disconnect resistances 305 from the mains. The operation of relay J will be explained later.

The E. M.' F. of the exciter 307 builds up to its full value as the driving motor 300 comes up to full speed.4 As has been stated previously,'the exciter supplies current for the iield 310 of the elevator motor 306. Ac'- cording to the preferred arrangement however, with the motor' generator set running but with the elevator motor at rest, this current is reduced providing what may be termed a standing field. The resistance 328 is employed for this purpose. The elevator motor iield circuit may be traced from the left hand exciter terminal 381, line `382, by Way ofline 383 through iield 310,

coil J 380, resistance 328 and ,contacts Z384 of the speed control switch and contacts F 385 ofthe third accelerating switch arranged in parallel relation, line 386, to the right hand exciter terminal 387 lt is not desired to apply full exciter voltage to the field 310 when ,the elevator motor is not in operation because of increased power consumption. 0n the other hand, it .is not desired to have the iield 310 deenergized with the elevator motor at rest as a matter of s fety and because of the large time constant in olved in building up.

As has previously been explained, contacts L 378 separate as the driving'motor 300 comes up to full speed. The actuating coil J 380 of the minimum current eld relay, therefore, does not receive current until the exciter E. MF. is built up to substantially *full value.

standing field value, relay J operates to.

cause the engagement of contacts J 388. The circuit for the potential switch actuating coil A 390 is completed upon the engagement of contacts J 388 and may be traced from termi-l nal 381, line 382, by way of linie 391 through switch 354, contacts A 392, contacts J 388, coil A. 390 various safety-switches (indicated by legend 386, to terminalv 387. Thus the circuit for coil A390 cannotbe completed and therefore the potential switch cannot operate until the exciter E. M. F. has built up substantiallf to eldl full value and until the elevator jmotor 310 has built up substantially to full standy mg field value. J By this arrangement injury to the system such as'would result rom l dangerous speeds of the'elevator motor is andsafety switch 333 in the car, line prevented. In order that this may be clearly in normal7 for starting .I switch therefore being in its up seen, assume that the system is not provided with the relay J and the contacts L 378. Upon starting up, due to its large time constant, the elevator motor .field 310 builds up much more slowly than the E. M. F. of the exciter.' Thus the potential switch would opei'ate beforey the elevator motor field built up and, if the operator had thrown the master controlswitch to position II to start the car immediately after closing the start control switch, lthe elevator motor would start up on a weak field and would tend to run away. By providing the system with the minimum current field relay J, starting the elevator motor on a Weak field in this manner is prevented sincethe motor field current must be of sufficient value to effect the operation of the relay. As a further example, assume that the system is provided with the minimum current field relay but not With the contacts L 378.- Should the start control switch be opened after the elevator motor field has built up, the current through coil J 380 would reduce slowly, due to the large time constant of the elevator motor field. Thus if the start" control switch should be closed and the master control switch should be moved to start position before the relay J dropped out to break the potential switch coil circuit, again the elevator 'motor might be caused to operate with a weak field due to the exciter E. M. F. building up relatively rapidly. By providing the s stein with the contacts L 37 8, starting the e evator motor on a weak field in this manner is prevented since the contacts J 388 are separated immediately the start control switch 355 is opened. More specifically, opening of switch 355 deenergizes the actuating coil M 356 of the driving motor starting relay. Contacts M 362, therefore, separate, deenergizing coil L 365, the contacts L 378 engaging in turn to short circuit the coil Assuming then that contacts J 388 are and that coil A 390 is energized, the

closed potential switch operates to cause the engagement of contacts A 394, A 395 and A 396 and to cause the separation of contacts A 392. The engagement of contacts A 394 and A 395 prepares the circuit for-the generator separately excited field and thevarious control circuits. The engagement of contactsA 396 connects the discharge resistances 332 and 333 in parallel across the brake release coil 330. The separation of 'contacts A 392 inserts the cooling resistance 397 in Series with the actuating coil A 390.

Assuming that the above described operations have heen completed,

operating condition,i. e., ready the car. For convenience of description, it is further assumed that the car is at rest at the first floor, the director position `tor switch V, upon operation,

the system is now with segment 44 bridging contacts 40, 33, 36 and 37, asl illustrated. In the starting operation, the operator first moves the master control switch to position I to cause the closure of the gate and door. As previously explained, the master control switch contact bar 348 bridges contacts 345 in position I to cause the operation of the gate closing mechanism. F or`convenience of description, contacts 345 are arranged to complete a circuit foi the gate motor switch actuating coil V 398 and the maintaining relay actuating coil W 399. The circuit for these coils may be traced from terminal 381, by Way of line 382through contacts A 394, line 400, byway of line 401 through coil V 398, coil W 399 and contacts 345, back to line 400, line 402, switch 393, line 391, line 386, to terminal 387. The gate mocauses the engagement of 'contacts circuit for the gate operating motor 338. This circuit may be traced by way of line 382 through contacts A '394, by way of line 400 through resistance 404, contacts V 403, gate motor armature 340 and field 341, line 402, switch 393, line 391, line 386, to terminal 387. The maintaining relay V, upon operation, causes the engagement of contacts IV 405 to by-pass master control switch contacts 345 maintaining coil V 398 energized. c f

Referring briefiy to Figure 1, the gate motor 338 operates through linkage 406 to move valve 407 for gate engine 408 to gate closed position and to withdraw the retiring cani 409 from engage-ment with the roller provided on the end of the door engine valve lever 410. The lever 410 is operated by a spring tomove valve 411 for the door engine 412 to door closed position. The gate and door engines operate through mechanism not shown to close the gate and door.

Referring again to Figure 17, if the operator, at any time after he has closed the gate and doorand before he has advanced the master control switch to open the gate and arrest the movement to position II, desires door, or if he desires to while the gate and door are closing, he may do so by moving the master control switch to positionIH. Contacts 343 are thus bridged short-circuiting coil W 399 by means of a circuit comprising contacts D 413 on'the first The maintaining relay drops out separating contacts W 405 to remove the by-pass for contacts 345. Coil V398 isl thus deenergized V 403 completing the from terminal 38l,

accelerating switch.

and the contacts V 403 separate breaking the circuit for the gate operating motor.A The spring 414, shown in Figure 1, operates tomove -valve 407 and, through cam 409 and lever 410, valve 411 to positions to cause the reverse operation of the engines 408 and 412 to open the gate and door. Obviously other forms of power operated gate and door mechanisms and arrangements for controllingsuch mech- .i anis'ms may be employed without departing` from the spirit of the present invention.

Assuming that the gate and doors are closed, the gate contacts 415 and a series'ot door contacts, indicated by a single set'of contacts 416, are in engagement. rlhe opgnator may now move the master control switihto position II bridging contacts 344 vand contacts 346. Contacts 344 prepare control circuits to be completed by the automatic switches and complete a circuit for the actuating coil P 417 of the up non-interference relay. rlhe circuit for coil P 417 maybe traced from terminal 381, by way of line 382 through con- -tacts A 394, by way of line 418`through Acoil P 417, contacts 33 and 40bridgedbythedirector switch segment 44, line 420, lby way of line' 421 through contact-slt 422 ofthe door contact sequence relay, doorcontacts416, gate contacts 415 and contacts 344, line 402, switch 393, line 39,1line 386, to terminal-387. rlhe operatiouof the up non-interference relay.l causes the engagementl of contactslD 423 to prepare a cincuit. for thev up -direction switch actuating c'oil li 424, the motor tieldswitch actuating coil H 425, and one coil 1426 of the door contactsequencerelay. The operaf sequence switch tionof the upnon-interference relay also causes theaengagemnt'f contacts P 427' .which,;.'with contacts 346 bridged, completes a circuit for the pawl magnet coil 231. ,The circuit for the pawl magnet coil may be traced from terminal 381, by way o line 382 through contacts A 394, by way of line 428 through consecutive-stop switch 430 in the car, con* secutiVe-stop switch 431 "(to be referred to later), contacts 346, coil 231, contacts US 432 of the up stop switch'and contacts DS 433 of the down stop switch, by way of line 434 throuffh'contacts P 427 and limit switch 284,

line 4:62, switch 393, line 391, line 386, to terminal 387-'. y Y Upon the energization of it-scoil, the pawl vmagnet retracts its'pawls 248 and'250 allow- Iing the automatic switches to close. 'As

has previously been explained, the up aui and up automatic stop switch 147,.director switch contact 33, segment 44 and con 'tact 40, line 420, by way of line 421 through contacts I 422, door contacts 416, ate contacts v 415 and contacts 344, line 402,.sw1t ch 393,l1ne to terminal 387. The circuit for* 391, line 386, coil 435 may. 1oe traced rom'termmal381,

by way by way of line 437 through coil I 435 and up automatic door sequence switch 148, by way of line 421 through contacts 344, line 402, switch 393, linel 391, line 386, to terminal 387. The up automatic switches 145 a`d=146 prepare circuits for the actuating coils of the accelerating switches. It is tobbe noted that, although the down automatic switches are closed, no circuit can be completed bythem since the director switch is in up position.

The purposeof the relay l is to insure the closure of the gate and doorsbefore starting the car. The coils It v426 and l 435, being differentially wound, 0p-A pose each other, when energized simultaneously, to prevent the operation of the relay. lf either coil 1426 or coil l 435 is energized ahead of the other, or if either coil alone' is energized, contacts I 422 open preventing the starting of the car. lf, when the automatic of line 382through contactsA 394,

door Contact sequence switches 147 and 148are closed, either the' gate contacts 415 or any of the door contacts 416 are. open, coil l 435 alone is energized resulting in the separation of contacts l 422. The separation ot contacts l 422 breaks the circuitfor coil l 426, maintaining the door Contact sequence relay operated, and for coil B424, preventing the operation of the up l direction switch and therefore the starting of the'car. Contacts 345 therefore are bridged ahead of contacts 344 and 346to eect the closure of the gate and door'contact before the automatic switches are closed. However,

ist the master control switch is moved from yposition l to pos1t1on ll too soon, 1. e., so as to cause the closure of the automatic switches before the closure of door Vand gate contacts, the door contact sequence .relay -operates to prevent the starting of the car.

ln this manner, starting of the cer on the gate contacts is prevented. Assuming that the door contact sequence relay has operated,

'in order to start the carthe master control switch is returned to neutral position deenergizing both coils l 426v and l 435, permitting contacts l 422 to re-engage. lf the gate anddoor are not closed, the master control switch is again moved to position I to cause` the closure of the gate and door and then to position ll to cause the starting of the car. lf the vgate and door are closed, the master control switch may be moved immediatelyfback toposition ll. It is believed,

obvious from the'description of the automatico 12o tloor stop machine that the automatic switches, once closed, remain so v,until another stop is made. Thus the circuit forvboth coils l 426 and 1435 in the above described operation is'rcmade by masterv control contact s lt is preferred to provide thedirection switches with a mechanical interlockto pre- 'vent their simultaneous o eration. gSuch an rlock m o-the @fe-cf Walking 13.0" 

